Known stereoscopic display devices that allow naked eyes to enjoy stereoscopic images include parallax barrier-based ones and lenticular lens-based ones. These stereoscopic display devices use barriers or lenses to separate light to show different images to the left and right eyes to allow the viewer to perceive depth. Currently, the main commercially-available stereoscopic display devices for naked eyes are 2-viewpoint parallax barrier-based and lenticular lens-based ones.
In the context of these 2-viewpoint stereoscopic display devices, the viewer perceives good stereoscopic imagery when he is in the designated region; however, when he moves his head to certain regions, an image to be seen by the right eye and an image to be seen by the left eye may be mixed and perceived as a double image, a phenomenon called crosstalk, or an image to be seen by the right eye may be seen by the left eye, i.e. so-called reversed-stereoscopy state. As such, the viewer can only view stereoscopic images from a limited region. To solve these problems, multi-viewpoint techniques as well as tracking techniques that detect the position of the head of the viewer and display images based on this position have been proposed.
JP 2011-18049 A describes a luminance flicker control apparatus for a wide-viewing angle stereoscopic display. This luminance flicker control apparatus includes: a video input unit mounted at a predetermined position of the display panel for capturing a real-time video of a viewer; a control unit for extracting the position and coordinates of the eyes of the viewer from the real-time video and controlling the operation of the stereoscopic video display in response to changes in the viewing angle of the viewer; and separation barrier electrodes controlled by the control unit to turn on and off to create stereoscopic video. The control unit applies a predetermined voltage to the separation barrier electrodes and adjusts the transmittance characteristics encountered when a separation barrier electrode is on to remove luminance flickering.